In a communication network, a SLA is signed between a service provider (SP) and a user to ensure the quality of communication services. The SLA is a formal agreement, through which the SP provides differentiated services for the user. The SP ensures the QoS to fulfill the SLA, and compensates or gives a discount to the user when the QoS is violated, namely, the QoS does not meet the requirements specified in the SLA. In the SLA, the user may subscribe to QoS at different levels, for example, platinum, gold, silver or bronze, and subscribe to the corresponding tariff. When the user enjoys the service at a specific level provided by the SP, the user needs to pay according to the payment terms specified in the SLA.
In practice, one user may need services at different levels in different scenarios. For example, after subscribing to a virtual private network (VPN) service, an enterprise user usually needs to ensure a high level of service in the business hours to ensure normal business operations, and intends to pay a higher tariff for the service; in non-business hours, the enterprise user usually needs a lower level of service to perform ordinary activities, and intends to pay a relatively lower tariff. Moreover, in the digital telephone services, an individual may expect cheap services rather than a high level of service because a moderate packet loss ratio and a moderate call drop ratio are tolerable in an ordinary conversation. On some important occasions, for example, telephone banking for ordering goods, and an important conference call, the user expects a relatively higher level of service and intends to pay a higher tariff. Therefore, it is necessary to provide QoS at different levels and provide the corresponding SLA assurance.
In the related art, the technical solution to providing multi-level QoS for a user and providing the corresponding SLA assurance is: When a user requires multi-level QoS for the same service, the SP signs multiple independent SLAs with the user for each required service level. Such SLAs are not correlated, and are usually signed by different user identities. A specific user identity is used for a service at a specific level, and the user enjoys the service specified by the corresponding SLA.
In the technical solution of the related art, the user signs different SLAs for the same service. Because the user identities are independent and not correlated, the user may pay for the same service at different levels repeatedly. For example, in the email service, if a user applies for a platinum mailbox and an ordinary mailbox, the user may have to pay for the two mailboxes for the same email service. Generally, if the user requires a higher level of service, the user chooses to pay only a higher tariff (for example, a platinum mailbox) rather than enjoying services at multiple levels.
Furthermore, the user is unable to switch between the service levels corresponding to the independently signed SLAs. Generally, a user must select a specific user identity at the beginning of enjoying a specific service, and accept the service level corresponding to the SLA signed by the user identity. For example, in the email service in the related art, a user is unable to send important business emails through a higher service level at a higher tariff and send less important emails through a lower service level at a lower tariff to reduce the corresponding service expense.
Moreover, to obtain multiple levels of service, a user must have multiple independent identities for signing multiple independent SLAs, or even purchase multiple service terminals or resources, thus increasing the expenses. For example, to apply for a platinum service level and a bronze service level in the digital telephone service, a user may need two different telephone numbers.
Therefore, a solution is required to enable a user to subscribe to more than one service level with the same user identity, and to ensure the QoS at different levels for the user.